Breathing assistance systems such as ventilators and CPAP devices are used to provide various types of breathing assistance to patients. Typically, a patient is connected to a breathing assistance system by a connection system, which may include, for example, a patient circuit, a mask, nasal pillows, tracheal tube, and/or other conduits and connection devices. In some breathing assistance systems, the pressure delivered to the patient, or the pressure at the patient end of the connection system, is useful to the breathing assistance system, e.g., as feedback to the breathing assistance system or as an input for controlling the operation of the breathing assistance system.
When delivering gas to a patient via a patient connection system, it is often difficult or unfeasible to measure the pressure near the patient end of the connection system. Thus, pressure may be measured near the gas delivery device of the breathing assistance system (e.g., the ventilator outlet or CPAP box). In some instances, the pressure sensor is located within the ventilator or CPAP box housing. However, as known in the field, the pressure measured near the gas delivery device (i.e., near the end of the connection system opposite the patient) may not provide the most accurate data regarding the pressure at the patient end of the connection system, based at least in part on pressure drop effects in the patient connection system.